Printing machine



April 23, 1968 H. G. HARRISON PRINTING MACHINE 4 Sheets-Sheet 1 Filed July 28, 1966 M m 2% f M Z $17 j m/ w P MW m Apri 23, 1968 H. G. HARRISON 3,379,129

PRINTING MACHINE Filed July 28, 1966 4 Sheets-Sheet 2 I Inve In 4 #5255226 haze/so A tloi'ne ys April 23, 1968 H.G.HARRISON 3,379,129

PRINTING MACHINE Filed July 28, 1966 4 Sheets-Sheet 5 wlaw Attorneys I April 23, 1968 H. G. HARRISON PRINTING-MACHINE 4 Sheets-Sheet 4 Filed July 28, 1956 Attorneys United States Patent 3,379,129 PRINTING MACHINE Herbert G. Harrison, Enfield, England, assignor to English Numbering Machines Limited, Enfield, England, a British company Filed July 28, 1966, Ser. No. 568,576 Claims priority, application Great Britain, Aug. 21, 1965, 35,972/ 65 3 Claims. (Cl. 101-316) ABSTRACT OF THE DISCLOSURE The invention relates to a printing mechanism comprising a single mechanism for setting the mechanism to print alternatively under 2 different printing pressures, the mechanism is set for printing under a weak printing pressure when only a single sheet has to be printed and under a heavier printing pressure when a plurality of carbon copies are simultaneously to be made during printing. In the first case printing is effected under the action of a single-revolution clutch through two levers coupled together by spring means. In the second case movement of one lever is restricted so that during rotation of the single-revolution clutch the spring means are tensioned whereupon the restriction of said lever is removed and printing is effected under the action of the spring means.

Disclosure of the invention The present invention relates to printing mechanisms.

For some purpose, for example for manually operable printing machines for printing numbers sequentially, it is desirable toprovide a printing machine which enables the printing pressure to be varied so that a light printing pressure can be employed when single sheets are printed and a heavy printing pressure can be employed when a number of copies are made simultaneously with the printing by means of carbon paper.

It is an object of the invention to provide a printing mechanism in which the printing pressure is controllable.

The invention consists in a rinting mechanism comprising a printing unit arranged to carry out a printing movement in response to operation of a control mechanism, wherein the control mechanism comprises a spring means and an adjustable pressure control member which, for varying the printing pressure of the printing unit, is movable into a first position and into a second position, the arrangement being such that the spring means are stressed during the printing movement by an amount which varies in dependence .on the position of the pressure control member.

Other objects and advantages of the invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings which are given by way of erample and in which:

FIG. 1 shows a side view of a printing mechanism;

FIG. 2 shows a side view corresponding to FIG. 1 but with some parts of the machine omitted and with other parts in different positions;

FIG. 3 shows, in side view, parts of the machine of FIGS. 1 and 2 during operation of the machine;

FIG. 4 shows a view taken in perspective of a support member;

FIG. 5 shows a view, taken in perspective, of a lever provided with side walls having guide slots;

FIG. 6 shows a view, taken in perspective, of a stoparm;

FIG. 7 shows a view, taken in perspective, of parts of a parallel motion linkage; and

FIG. 8 shows a view of parts of the mechanism of FIGS. 1 and 2 viewed from the opposite side of the machine.

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As shown in FIG. 1, the machine has a base 1 on which a support plate 2 is mounted by means of a pedestal 3. Four side plates 5, 6, 7 and 8 (see FIGS. 1 and 8) extend upwardly from the base 1 and carry the parts of the machine described below.

A printing unit 10 of the type which prints numbers sequentially is carried by four support arms 11 and 12 (see FIGS. 1 and 7). The support arms 11 are connected by ivot pins 14 to opposite sides of the printing unit 10, only one of the pivot pins 14 being illustrated in the drawings, and are freely pivota-ble about a shaft 15 (see also \FIG. 2) journal'led in the side plates 5 and 6, the arms 11 being connected rigidly together by a plate 16. The arms 12 are respectively connected to the arms of a U-shaped bracket 18 by pivot pins 19, of which only one is shown.

A plunger rod 20 projecting upwardly from the printing unit 10 is fixedly secured at its upper end to a collar 21 which, on opposite sides, is provided with projecting pins 22, of which only one is shown, the pins 22 slidably engaging in arcuate guide slots 24 (FIGS. 1 and 5) in depending side walls 25 of a lever 26.

This lever 26 is fixedly secured to a shaft 28 journalled in the side walls 5 and 6, the lever 26 extending from between the side walls 5 and 6.

The support arms 12 are freely pivotable about a shaft 29 (FIG. 7), which extends between but not into the side plates 5 and 6, and are rigidly joined together by a plate 30 which is formed with a cutout 31 through which the side walls 25 of the lever 26 extend.

Means for turning the printing unit 10 are provided in the form of a lever 33 (FIG. 1) fixedly secured to the shaft 15 by a screw 34 and carrying a knob 35 attached to a spring pin 36 which extends through the lever 33 and is engageable either in a recess in a retainer 37 secured to the side Wall 5 or, by pivoting of the lever 33 about the axis of the shaft 15, in a recess in a retainer 38 secured by a bracket 39 to the side plate 5. By pivoting the lever 33 from the position shown, in which the pin 36 engages in the retainer 37, into the position in which the pin 36 engages with the retainer 37, an arm 40 secured to the shaft 15 (see FIG. 7) and engaging the shaft 29 causes the shaft 29 to rotate about the axis of the shaft 15 so that by means of the arms 12 the printing unit 10 is tilted, the projecting pins 22 sliding along the guide slots 24 and causing the plunger rod 20 to be pushed into the printing unit 10 to bring the type wheels to an opening (not shown) in the bottom of the printing unit 10 where they are readily accessible for adjustment purposes. During this movement of the parallel motion linkage formed by the arms 11 and 12, the printing unit 10, the bracket 18 and arms 41, which are freely rotatably mounted on the shafts 15 and 29 and rigidly secured together by a plate 42, the arms 11 are held stationary by a support arm 43 (FIGS. 1 and 4) engaging one of the arms 11. The support arm 43 is carried on the shaft 15 and is joined to a downwardly extending arm 44 which is bent at its free end to form an abutment lug 45.

One end of a lever 47 is formed with a slot 49 which slidably receives a pin 50 extending from a first lever 51. When the lever 51 is in the position in which it is shown in FIGS. 1 and 4, it abuts the lug on the arm 44 to hold the support arm 43 in position. The lever 51 is rigidly secured to the shaft 28, and, at the side of the lever 51 opposite to the pin 50, has 'a first abutment member in the form of a projection 53. A strong tension spring 52 is secured at one of its ends to the pin and at its opposite end to a pin 48 on the lever 47. The first lever 51 constitutes first means for moving the printing unit 10 into printing position, and the lever 47 constitutes a second lever or second means for moving the printing unit 10 into printing position.

A printing pressure control member comprising a pressure control knob 54 earring a pin 97 is rotatably secured to the side plate 5, and one arm 55 of a two-armed control lever projects into an annular slot 56 in the knob 54. The arm 55 is urged radially inwardly of the slot 56 by means of a tension spring 57 which is secured at one of its ends to the bracket 39 and at its other end to another arm 58 of the two-armed lever. This arm 58 acts as releasing means. The arm 58 has a stop shoulder 98 acting as a second abutment member and is formed with a recess 59 into which extends the projection 53 acting as limiting means. Said two-armed control lever constitutes control means for controlling the printing pressure.

A single revolution clutch indicated generally by reference numeral 60 is mounted on the side plate 7 and comprises a driven clutch member in the shape of a disc 61 formed with a recess 62 containing a tension spring 63 which, is secured at one of its ends to the disc 61 and at its other end to a pawl 65.

The pawl 65 is pivotally connected by a pivot pin 66 to the disc 61 and has a projecting arm 67 which, in the position shown in FIG. 1, is retained by a lug 69 so that a projection 70 on the pawl 65 is held out of engagement with the toothing of a toothed wheel 71 which is co-axial with the disc 61.

The lug 69 is provided on one arm of a two-armed lever 74 secured by a pivot pin 75 to the side plate 7, the other arm of the lever 74 being urged by a tension spring 76, which is secured to the lever 74 and to the side plate 5, against a lug 78 projecting laterally from a manually actuable lever 79. The lever 79 extends be tween the side plates 5 and 6 and is pivotably secured to the side plate 5 by a pivot pin 80. A finger rest 82 is provided on the end of the lever 79 opposite to the lug 78.

Means on said driven clutch member in the form of an abutment pin 83 projecting from the rear of the disc 61 towards the side plate 7 co-operates with a support lever 84. This lever 84 is pivotable about a pivot pin 851 secured to the side plate 7 and urged by a tension spring 85 against an abutment pin 86 projecting from the side plate 7, the tension spring 85 being secured to the lever 84 and the side plate 7.

The lever 47 is pivotably secured to the disc 61 by a pivot pin 88.

A shaft 90 extending between and abutting against the side plates 5 and 6 is supported by a pair of screws 91 which are in threaded engagement with holes formed in the shaft 90 but offset from the axis of the shaft 90,

and which extend through the side plates 5 and 6 and rigidly but adjustably secure the shaft 90 to the side plates 5 and 6. A stop arm 93, through which the shaft 28 extends, is formed at one end with a laterally extending lug 94 (FIGS. 1 and 6) and at its opposite end with a slot 95 which receives the shaft 90. The lug 94 serves to limit upward movement of one of the arms 12, and thus of the printing unit 10, when the rod 20 is pulled upwardly from the printing unit 10 into the position shown in FIG. 1 by the lever 26. This ensures that the type wheels of the printing unit 10 are pressed against an inking pad (not shown) even when the machine is not in operation. By loosening the screws 91, rotating the shaft 90 and then re-tightening the screws 91, the position of the lug 94 can be adjusted.

An electric motor (FIG. 8) is arranged for driving the toothed wheel 71 through a reduction gearing comprising gears 101 to 106, to rotate a shaft 108 journalled in the side plates 7 and 8 and carrying the toothed wheel 71, which is fixedly secured to the shaft 108.

A normally open microswitch 110 on the side plate 6 is actuated by an arm 111 on the shaft .15 and serves to interrupt the current supply to the electric motor 100 when the shaft 15 is pivoted to allow the type wheels of the printing unit 10 to be adjusted as described above.

The operation of the machine is as follows:

For printing with a light printing pressure, for example when printing only one copy at a time, the pressure control knob 54 is rotated to bring the pin 97 thereon into contact with the lever arm 55 to pivot the arm 58 about the shaft 15 into the position in which it is shown in FIG. 2. This pivoting moves the stop shoulder 98 on the arm 58 into a predetermined first position in which said stop shoulder lies out of the path of travel of the projection 53 on the lever 51 on pivoting of the lever 51 abut the axis of the shaft 28. The machine is then. ready for operation with a light printing pressure.

The electric motor 100 is energized and the toothed wheel 71 begins to rotate, but no drive is transmitted from the toothed wheel 71 since the projection 70 is disengaged from the toothing of the toothed wheel 71.

After placing a sheet of paper to be printed on the support plate 2 beneath the printing unit 1, the finger rest 82 is manually depressed to pivot the lever 79 about the pivot pin 80 and thus to pivot the lever 74 so that the lug 69 is disengaged from projection 67.

When this happens, the projection 70 on the pawl 65 is urged by the spring 63 into engagement with the toothed wheel 71 so that drive is transmitted from the toothed wheel 71 to the disc 61. Rotation of the driven disc 61 draws the lever 47 to the right, as shown in FIG. 2, and the movement of the lever 47 is transmitted through the spring 52 to the lever 51 which, through the shaft 28, causes the lever 26 to pivot downwardly so that the printing unit 10 descends onto the paper and eifects a print. As the disc 61 continues to rotate from the position shown in FIG. 2 back to its initial position, the lever 47, and thus the printing unit 10 are returned to their initial positions.

The projecting arm 67 of the pawl 65 again strikes the lug 69, which in the meantime has been returned to its initial position by removal of the operators fingers from the finger rest 82. When the projection 67 strikes the lug 69, the pawl 65 is disengaged and the disc 61 is no longer driven. The projection 83 then. rests on the support lever 84 and prevents reverse rotation of the disc To set the machine for printing with a heavier printing pressure, for example for simultaneously making a number of copies by means of sheets of paper interleaved with carbon paper, the pressure control knob 54 is rotated into the position shown in FIG. 1 so that the projection 97 is moved away from the arm 55 and the stop shoulder 98, under the action of the spring 57 of the arm 58, moves into a predetermined second position in which said stop shoulder lies in the path of the projection 53.

When the finger rest 82 is then depressed and the disc 61 is caused to rotate as described above, the lever 5'1 pivots about the axis of the shaft 28 until the projection 53 abuts against the stop shoulder 98. On further rotation of the disc 61, the spring 52 becomes tensioned. Eventually, the abutment pin 83 on the disc 61 strikes the tip of the arms 58, as shown in FIG. 3, and pivots the arm 58 about the shaft 15 and thus releases the projection 53. The lever 51 is then free to pivot and the printing unit 10 is driven down towards the support plate 2 under the action of the spring 52.

No adjustment of the above-described mechanism to take into account variations in the thickness of the sheet or sheets being printed is necessary.

The finger rest 82 must be depressed and released for each printing operation, thus reducing the chance of inadvertent and incorrect printing.

It should be clearly understood that the embodiment described is given by way of example and that modifications, additions and omissions are possible without de parting from the scope and spirit of the invention.

I claim:

'1. In a printing mechanism comprising a printing unit, a single-revolution clutch having a driven member, and spring means for urging said printing unit into printing position, said spring means being tensionable prior to printing, the combination of: first means linked to said printing unit for moving said printing unit into printing position, second means linked through said spring means to said first means, said second means being movable by said driven clutch member, control means, mean-s for limiting movement of said first means when said control means is in one predetermined position, said limiting means allowing free movement of said first means when said control means is in another predetermined position, and means on said driven clutch member for releasing said first means after its movement has been limited by said limiting means, said first means freely following movement of said second means in response to movement of said driven clutch member when said control means is in said other position to operate said printing unit by said driven clutch member through said first means and said second means, whereas when said control member is in said one position and after said limiting means have limited movement of said first means, said spring means are tensioned by said second means in response to movement of said second means by said driven clutch member and, after release of said first means by said releasing means, said first means is moved and operates said printing unit under the action of said spring means.

2. A combination as defined in claim 1, and further comprising means for turning said printing unit independently of said clutch for facilitating setting of said printing unit.

3. In a printing mechanism comprising a printing unit,

a single-revolution clutch having a driven clutch member, and spring means for urging said printing unit into printing position, said spring being tensionable prior to printing, the combination of: a first lever linked to said printing unit for moving said printing unit into printing position, a second lever linked through said spring means to said first lever and pivoted to said driven clutch member, a control member, a control lever movable by said control member, a first abutment member on said first lever, a second abutment member on said control lever, said second abutment member lying out of the path of said first abutment member when said control lever has been moved by said control member into a predetermined first position in which said first lever can freely follow said second lever to operate said printing unit under the action of said driven clutch member, said second abutment member lying within the path of said first abutment member when said control lever has been moved by said control member into a predetermined second position to enable said first abutment member to strike said second abutment member thereby limiting movement of said first lever and causing said spring means to be tensioned on movement of said second lever in response to movement of said driven clutch member, and means on said driven clutch member for moving said control lever out of its second position towards said first position to release said first abutment member from said second abutment member and to enable said first lever to move and to operate said printing unit under the action of said spring means.

References Cited UNITED STATES PATENTS 8/1932 Hubbard 101-297 2/1938 Fromm 101--216 X 

